Vasculopathy encompasses a group of vascular diseases, which includes atherosclerosis, a major disease with enormous societal impact. Atherosclerosis is implicated in many cardiovascular diseases including myocardial infarction, peripheral vascular disease, and stroke. Approaches have been proposed for improving diagnostics, where inconclusive or misleading information can lead to under- and over-treatment. Additionally, better biomarkers are needed for use in developing more effective drugs for vasculopathies. Arterial stenosis as a biomarker is a poor predictor of events, yet it remains in common use. This burdens care providers with high misclassification rates. Detection of the so-called vulnerable plaque has demonstrated promise, but it is not without controversy and may be unlikely to achieve widespread adoption because it still relies on detecting one or a handful of surrogate features, that are based on limited autopsy studies. Elucid Bioimaging's vascuCAP (CAP stands for Computer Aided Phenotyping) processes magnetic resonance imaging (MRI) and/or computed tomography (CT), both of which are routinely used in vascular diagnostics. CAP aids the clinician with a multi-factorial quantitative imaging biomarker panel of specific, biologically-objective, and continuous-valued measurements such as distribution of lipid core and other determinants of lesion phenotype and severity. Recognizing the pros and cons of different imaging modalities with respect to any given patient's needs, vascuCAP is developed as a multi-modality analysis capability that maximizes the information content from whatever modality is available for that patient, whether CT (which is fast and generally leads to the most accurate measurements of structure but which utilizes ionizing radiation) or MR (which is currently most capable of measuring composition, avoids ionizing radiation, but takes more time to acquire). Our primary goal is to improve patient management by aiding therapeutic decision-making for both symptomatic and asymptomatic patients by combining the vascuCAP analysis of vascular imaging with the other objective patient data, i.e. clinical chemistry and other blood biomarkers. It may also be used to improve speed and efficiency in developing new therapeutics. We have recently completed feasibility studies in both animal models as well as human atherosclerosis that serve as the scientific rationale for the proposed study. This Phase II study will determine the MRI and CT characteristics of atherosclerotic plaques and compare them to reference truth standards including histopathological analyses of arterial endarterectomy specimens. We have established probable clinical utility in animal models as well as in human studies. This Phase II SBIR study will determine the degree to which vascuCAP analysis results, obtained in larger numbers of carotid and peripheral arteries, are similar to those obtained on ex-vivo histology and whether relevant reference measurements in the coronary arteries are in accordance with prior feasibility studies.